Had an email response from GTC and maybe the dock feature means geofence is no longer required. I would be more concerned of how long the battery would last (I have the attached file containing battery performance - so pm me if you would like a copy) but maybe it could be hardwired in.
Thanks for your email.
If you are using the device purely for tracking your boat and nothing else I would definitely recommend the SPOT Trace as this has been designed with boats in mind and has a ‘Dock Mode’ to allow for slight movements:
For assets stored on the water, where vibration would cause false tracking, enable Dock Mode to help eliminate tracks caused by waves while the boat is safely docked. When Dock Mode is enabled, Trace uses the vibration sensor and location to determine if track messages should be sent. Based on the assumption that a boat will be moving continuously when docked, Trace compares GPS readings to determine if the boat is actually changing locations. When a couple of GPS readings are the same, it will suspend Tracking. The device will continue to obtain readings from the GPS at whatever rate Tracking is set to (2.5 min, 5 min etc.) When two readings are more than 200 meters apart, Tracking will resume. If the boat is stationary and motion is low enough that vibration is not detected, Tracking can also be suspended due to lack of movement.
If you need to use the device for advanced features like SOS then SPOT 3 would be more suitable although this does not have the dock mode so could potentially send out tracking locations when the boat hasn’t moved anywhere.
Both devices require an annual service plan to operate. Please note that if you choose the basic service plan with SPOT the tracking feature is limited to a minimum of 10 minutes and needs to be reset after 24 hours. It is therefore recommended that you go for the Unlimited Tracking plan which allows for 5 minute tracking with no reset after 24 hours (it will transmit continually until movement stops).
The annual service plans include the online configuration tool and mapping software.
The tracking messages can be sent automatically by email e.g. if SPOT Trace detects movement it will send an email to advise you of this.
I have attached the estimated battery life of SPOT Trace although this assumes a lot of movement. In our testing, it has lasted for three months so far with needing a recharge (this is with occasional movement twice a day and stationary the remainder).
Finally, please note that the SPOT Trace is not currently available in the EU but will be shortly. The airtime plans have not yet been finalised but will likely be similar to Spot 3.
Please let me know if you have any questions.